I used a very similar item and both the negative and positive reviews have truth to them. Here's my 2 cents worth.
Drill a tiny pilot hole. I think you could hammer in a small nail for a starter hole. Even with a hole drilled it took some effort for me to work the wire through.
If you use a twisting motion to work the wire in, it's important to keep the wire straight (horizontal) or else it WILL make an enlarged hole from spinning around at an angle. Even with care, the hole is definitely bigger than the pinhole I was imagining, but way smaller than a hole from an anchor.
I needed to grip the wire with pliers for the final push in. It's important to get that bend in the wire right up against the wall and I couldn't do that with my bare hands.
You need empty space behind the drywall but this thing does not have to spin a full 360.ş You need empty space behind and above the point of insertion. The wire will slide in along its curve but it takes a little care and effort. Once you do it you'll get a feel for it. You could even practice on an old piece of drywall or heavy cardboard.
I used these on standard drywall, not sure if it's half inch or five eighths.
These work in the particular situations where they work. If there's nothing behind your drywall, a nail is not going to work unless you're hanging a piece of paper. And if there's a stud behind your drywall, go with that--a stud trumps all.
I used these to hang two shower caddies at the back of the tub, just above the tub surround. They are holding up great with lots of bottles of shampoo, etc. weighing them down and being lifted in and out. I was not sure if they are designed to hold something that gets used, as opposed to a picture just quietly hanging there.